3,455 research outputs found

    Algorithm for heart rate extraction in a novel wearable acoustic sensor.

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    Phonocardiography is a widely used method of listening to the heart sounds and indicating the presence of cardiac abnormalities. Each heart cycle consists of two major sounds - S1 and S2 - that can be used to determine the heart rate. The conventional method of acoustic signal acquisition involves placing the sound sensor at the chest where this sound is most audible. Presented is a novel algorithm for the detection of S1 and S2 heart sounds and the use of them to extract the heart rate from signals acquired by a small sensor placed at the neck. This algorithm achieves an accuracy of 90.73 and 90.69%, with respect to heart rate value provided by two commercial devices, evaluated on more than 38 h of data acquired from ten different subjects during sleep in a pilot clinical study. This is the largest dataset for acoustic heart sound classification and heart rate extraction in the literature to date. The algorithm in this study used signals from a sensor designed to monitor breathing. This shows that the same sensor and signal can be used to monitor both breathing and heart rate, making it highly useful for long-term wearable vital signs monitoring

    Optical Transistor for an Amplification of Radiation in a Broadband THz Domain

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    We propose a new type of optical transistor for a broadband amplification of THz radiation. It is made of a graphene--superconductor hybrid, where electrons and Cooper pairs couple by Coulomb forces. The transistor operates via the propagation of surface plasmons in both layers, and the origin of amplification is the quantum capacitance of graphene. It leads to THz waves amplification, the negative power absorption, and as a result, the system yields positive gain, and the hybrid acts like an optical transistor, operating with the terahertz light. It can, in principle, amplify even a whole spectrum of chaotic signals (or noise), that is required for numerous biological applications.Comment: 7 pages, 3 figure

    Vaccination of Cattle with the N Terminus of LppQ of Mycoplasma mycoides subsp. mycoides Results in Type III Immune Complex Disease upon Experimental Infection

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    Contagious bovine pleuropneumonia (CBPP) is a serious respiratory disease of cattle caused by Mycoplasma mycoides subsp. mycoides. Current vaccines against CBPP induce short-lived immunity and can cause severe postvaccine reactions. Previous studies have identified the N terminus of the transmembrane lipoprotein Q (LppQ-N') of M. mycoides subsp. mycoides as the major antigen and a possible virulence factor. We therefore immunized cattle with purified recombinant LppQ-N' formulated in Freund's adjuvant and challenged them with M. mycoides subsp. mycoides. Vaccinated animals showed a strong seroconversion to LppQ, but they exhibited significantly enhanced postchallenge glomerulonephritis compared to the placebo group (P = 0.021). Glomerulonephritis was characterized by features that suggested the development of antigen-antibody immune complexes. Clinical signs and gross pathological scores did not significantly differ between vaccinated and placebo groups. These findings reveal for the first time the pathogenesis of enhanced disease as a result of antibodies against LppQ during challenge and also argue against inclusion of LppQ-N' in a future subunit vaccine for CBPP

    Crop diversification and digestate application effect on the productivity and efficiency of irrigated winter crop systems

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    Irrigated winter crops can reduce input demands when compared with irrigated summer cropping systems in the Mediterranean area. The sustainability of these systems can be further improved resorting to diverse rotations, but also to fertilisation with digestate, a by-product from anaerobic digestion of organic waste. Post-treatments such as drying and acidifying can improve the fertiliser value of this product. In this study, we compare wheat performance in a three-year full cereal rotation or in a diverse rotation, with pea and canola. Besides, untreated and dried acidified digestates are tested as fertilisers for all crops, comparing to mineral fertilisation at a rate of 140 kg N ha−1 and a control with no fertilisation. To assess productivity and efficiency of the different systems, grain yield and N concentration, N uptake efficiency (NUpE) and water use efficiency (WUE) were determined, along with soil nitrate dynamics and total N at the end of the experiment. Results showed an average wheat yield increase of 1.79 t ha−1 by the last year of the diverse crop rotation rather than the cereal rotation (p < 0.001). Although there was no yield increase in the previous year, wheat after pea showed higher grain N concentration (p < 0.001). However, the NUpE of wheat remained steady due to a higher soil N availability after pea, which suggests that fertilisation can be adjusted. Although wheat WUE increased due to canola and pea precedents (p < 0.001), the cereal rotations should be more adapted to systems with low water availability. Nonetheless, both rotations required about 30% of irrigated water than the typical irrigated summer crops of the Ebro valley region. Fertiliser effect on yields was variable according to the tested crop mainly due to differences in N demand along each growing cycle. Overall, dried acidified digestate application resulted in similar soil nitrate levels than the mineral fertiliser. The diverse rotation raised soil nitrates content compared to the cereal rotation at sowing and harvesting times (p = 0.002 and p < 0.001, respectively). Higher soil nitrate levels were found when associating these two practices, while nitrate levels after mineral fertilisation showed to be less dependent on the implemented rotation. The diverse rotation also raised soil total N at the end of the experiment (p = 0.023). Similarly, the dried acidified digestate application resulted in higher soil total N than mineral fertilisation (p = 0.011). These findings show how these management practices should allow for a chemical fertilisation reduction in irrigated winter crop systems.This work was supported by the European Union’s Horizon 2020 Research and Innovation programme [Grant Agreement No. 773649] and by the State Agency of Research (Spain) [Projects AGL 2017/84529-C3–3R and PID 2021–126343OB-C33]. G. Nascimento is recipient of an UdL-IRTA PhD fellowship. The IRTA authors acknowledge the CERCA programme (Generalitat de Catalunya) contribution.info:eu-repo/semantics/publishedVersio
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